1 /* $NetBSD: fsmagic.c,v 1.7 2013/03/23 16:15:58 christos Exp $ */ 2 3 /* 4 * Copyright (c) Ian F. Darwin 1986-1995. 5 * Software written by Ian F. Darwin and others; 6 * maintained 1995-present by Christos Zoulas and others. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice immediately at the beginning of the file, without modification, 13 * this list of conditions, and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 /* 31 * fsmagic - magic based on filesystem info - directory, special files, etc. 32 */ 33 34 #include "file.h" 35 36 #ifndef lint 37 #if 0 38 FILE_RCSID("@(#)$File: fsmagic.c,v 1.67 2013/03/17 15:43:20 christos Exp $") 39 #else 40 __RCSID("$NetBSD: fsmagic.c,v 1.7 2013/03/23 16:15:58 christos Exp $"); 41 #endif 42 #endif /* lint */ 43 44 #include "magic.h" 45 #include <string.h> 46 #ifdef HAVE_UNISTD_H 47 #include <unistd.h> 48 #endif 49 #include <stdlib.h> 50 /* Since major is a function on SVR4, we cannot use `ifndef major'. */ 51 #ifdef MAJOR_IN_MKDEV 52 # include <sys/mkdev.h> 53 # define HAVE_MAJOR 54 #endif 55 #ifdef MAJOR_IN_SYSMACROS 56 # include <sys/sysmacros.h> 57 # define HAVE_MAJOR 58 #endif 59 #ifdef major /* Might be defined in sys/types.h. */ 60 # define HAVE_MAJOR 61 #endif 62 63 #ifndef HAVE_MAJOR 64 # define major(dev) (((dev) >> 8) & 0xff) 65 # define minor(dev) ((dev) & 0xff) 66 #endif 67 #undef HAVE_MAJOR 68 #ifdef S_IFLNK 69 private int 70 bad_link(struct magic_set *ms, int err, char *buf) 71 { 72 int mime = ms->flags & MAGIC_MIME; 73 if ((mime & MAGIC_MIME_TYPE) && 74 file_printf(ms, "inode/symlink") 75 == -1) 76 return -1; 77 else if (!mime) { 78 if (ms->flags & MAGIC_ERROR) { 79 file_error(ms, err, 80 "broken symbolic link to `%s'", buf); 81 return -1; 82 } 83 if (file_printf(ms, "broken symbolic link to `%s'", buf) == -1) 84 return -1; 85 } 86 return 1; 87 } 88 #endif 89 private int 90 handle_mime(struct magic_set *ms, int mime, const char *str) 91 { 92 if ((mime & MAGIC_MIME_TYPE)) { 93 if (file_printf(ms, "inode/%s", str) == -1) 94 return -1; 95 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, 96 "; charset=") == -1) 97 return -1; 98 } 99 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1) 100 return -1; 101 return 0; 102 } 103 104 protected int 105 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb) 106 { 107 int ret, did = 0; 108 int mime = ms->flags & MAGIC_MIME; 109 #ifdef S_IFLNK 110 char buf[BUFSIZ+4]; 111 ssize_t nch; 112 struct stat tstatbuf; 113 #endif 114 115 if (ms->flags & MAGIC_APPLE) 116 return 0; 117 if (fn == NULL) 118 return 0; 119 120 #define COMMA (did++ ? ", " : "") 121 /* 122 * Fstat is cheaper but fails for files you don't have read perms on. 123 * On 4.2BSD and similar systems, use lstat() to identify symlinks. 124 */ 125 #ifdef S_IFLNK 126 if ((ms->flags & MAGIC_SYMLINK) == 0) 127 ret = lstat(fn, sb); 128 else 129 #endif 130 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */ 131 132 if (ret) { 133 if (ms->flags & MAGIC_ERROR) { 134 file_error(ms, errno, "cannot stat `%s'", fn); 135 return -1; 136 } 137 if (file_printf(ms, "cannot open `%s' (%s)", 138 fn, strerror(errno)) == -1) 139 return -1; 140 ms->event_flags |= EVENT_HAD_ERR; 141 return -1; 142 } 143 144 ret = 1; 145 if (!mime) { 146 #ifdef S_ISUID 147 if (sb->st_mode & S_ISUID) 148 if (file_printf(ms, "%ssetuid", COMMA) == -1) 149 return -1; 150 #endif 151 #ifdef S_ISGID 152 if (sb->st_mode & S_ISGID) 153 if (file_printf(ms, "%ssetgid", COMMA) == -1) 154 return -1; 155 #endif 156 #ifdef S_ISVTX 157 if (sb->st_mode & S_ISVTX) 158 if (file_printf(ms, "%ssticky", COMMA) == -1) 159 return -1; 160 #endif 161 } 162 163 switch (sb->st_mode & S_IFMT) { 164 case S_IFDIR: 165 if (mime) { 166 if (handle_mime(ms, mime, "directory") == -1) 167 return -1; 168 } else if (file_printf(ms, "%sdirectory", COMMA) == -1) 169 return -1; 170 break; 171 #ifdef S_IFCHR 172 case S_IFCHR: 173 /* 174 * If -s has been specified, treat character special files 175 * like ordinary files. Otherwise, just report that they 176 * are block special files and go on to the next file. 177 */ 178 if ((ms->flags & MAGIC_DEVICES) != 0) { 179 ret = 0; 180 break; 181 } 182 if (mime) { 183 if (handle_mime(ms, mime, "chardevice") == -1) 184 return -1; 185 } else { 186 #ifdef HAVE_STAT_ST_RDEV 187 # ifdef dv_unit 188 if (file_printf(ms, "%scharacter special (%d/%d/%d)", 189 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 190 dv_subunit(sb->st_rdev)) == -1) 191 return -1; 192 # else 193 if (file_printf(ms, "%scharacter special (%ld/%ld)", 194 COMMA, (long)major(sb->st_rdev), 195 (long)minor(sb->st_rdev)) == -1) 196 return -1; 197 # endif 198 #else 199 if (file_printf(ms, "%scharacter special", COMMA) == -1) 200 return -1; 201 #endif 202 } 203 break; 204 #endif 205 #ifdef S_IFBLK 206 case S_IFBLK: 207 /* 208 * If -s has been specified, treat block special files 209 * like ordinary files. Otherwise, just report that they 210 * are block special files and go on to the next file. 211 */ 212 if ((ms->flags & MAGIC_DEVICES) != 0) { 213 ret = 0; 214 break; 215 } 216 if (mime) { 217 if (handle_mime(ms, mime, "blockdevice") == -1) 218 return -1; 219 } else { 220 #ifdef HAVE_STAT_ST_RDEV 221 # ifdef dv_unit 222 if (file_printf(ms, "%sblock special (%d/%d/%d)", 223 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev), 224 dv_subunit(sb->st_rdev)) == -1) 225 return -1; 226 # else 227 if (file_printf(ms, "%sblock special (%ld/%ld)", 228 COMMA, (long)major(sb->st_rdev), 229 (long)minor(sb->st_rdev)) == -1) 230 return -1; 231 # endif 232 #else 233 if (file_printf(ms, "%sblock special", COMMA) == -1) 234 return -1; 235 #endif 236 } 237 break; 238 #endif 239 /* TODO add code to handle V7 MUX and Blit MUX files */ 240 #ifdef S_IFIFO 241 case S_IFIFO: 242 if((ms->flags & MAGIC_DEVICES) != 0) 243 break; 244 if (mime) { 245 if (handle_mime(ms, mime, "fifo") == -1) 246 return -1; 247 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1) 248 return -1; 249 break; 250 #endif 251 #ifdef S_IFDOOR 252 case S_IFDOOR: 253 if (mime) { 254 if (handle_mime(ms, mime, "door") == -1) 255 return -1; 256 } else if (file_printf(ms, "%sdoor", COMMA) == -1) 257 return -1; 258 break; 259 #endif 260 #ifdef S_IFLNK 261 case S_IFLNK: 262 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) { 263 if (ms->flags & MAGIC_ERROR) { 264 file_error(ms, errno, "unreadable symlink `%s'", 265 fn); 266 return -1; 267 } 268 if (mime) { 269 if (handle_mime(ms, mime, "symlink") == -1) 270 return -1; 271 } else if (file_printf(ms, 272 "%sunreadable symlink `%s' (%s)", COMMA, fn, 273 strerror(errno)) == -1) 274 return -1; 275 break; 276 } 277 buf[nch] = '\0'; /* readlink(2) does not do this */ 278 279 /* If broken symlink, say so and quit early. */ 280 if (*buf == '/') { 281 if (stat(buf, &tstatbuf) < 0) 282 return bad_link(ms, errno, buf); 283 } else { 284 char *tmp; 285 char buf2[BUFSIZ+BUFSIZ+4]; 286 287 if ((tmp = strrchr(fn, '/')) == NULL) { 288 tmp = buf; /* in current directory anyway */ 289 } else { 290 if (tmp - fn + 1 > BUFSIZ) { 291 if (ms->flags & MAGIC_ERROR) { 292 file_error(ms, 0, 293 "path too long: `%s'", buf); 294 return -1; 295 } 296 if (mime) { 297 if (handle_mime(ms, mime, 298 "x-path-too-long") == -1) 299 return -1; 300 } else if (file_printf(ms, 301 "%spath too long: `%s'", COMMA, 302 fn) == -1) 303 return -1; 304 break; 305 } 306 /* take dir part */ 307 (void)strlcpy(buf2, fn, sizeof buf2); 308 buf2[tmp - fn + 1] = '\0'; 309 /* plus (rel) link */ 310 (void)strlcat(buf2, buf, sizeof buf2); 311 tmp = buf2; 312 } 313 if (stat(tmp, &tstatbuf) < 0) 314 return bad_link(ms, errno, buf); 315 } 316 317 /* Otherwise, handle it. */ 318 if ((ms->flags & MAGIC_SYMLINK) != 0) { 319 const char *p; 320 ms->flags &= MAGIC_SYMLINK; 321 p = magic_file(ms, buf); 322 ms->flags |= MAGIC_SYMLINK; 323 if (p == NULL) 324 return -1; 325 } else { /* just print what it points to */ 326 if (mime) { 327 if (handle_mime(ms, mime, "symlink") == -1) 328 return -1; 329 } else if (file_printf(ms, "%ssymbolic link to `%s'", 330 COMMA, buf) == -1) 331 return -1; 332 } 333 break; 334 #endif 335 #ifdef S_IFSOCK 336 #ifndef __COHERENT__ 337 case S_IFSOCK: 338 if (mime) { 339 if (handle_mime(ms, mime, "socket") == -1) 340 return -1; 341 } else if (file_printf(ms, "%ssocket", COMMA) == -1) 342 return -1; 343 break; 344 #endif 345 #endif 346 case S_IFREG: 347 /* 348 * regular file, check next possibility 349 * 350 * If stat() tells us the file has zero length, report here that 351 * the file is empty, so we can skip all the work of opening and 352 * reading the file. 353 * But if the -s option has been given, we skip this 354 * optimization, since on some systems, stat() reports zero 355 * size for raw disk partitions. (If the block special device 356 * really has zero length, the fact that it is empty will be 357 * detected and reported correctly when we read the file.) 358 */ 359 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) { 360 if (mime) { 361 if (handle_mime(ms, mime, "x-empty") == -1) 362 return -1; 363 } else if (file_printf(ms, "%sempty", COMMA) == -1) 364 return -1; 365 break; 366 } 367 ret = 0; 368 break; 369 370 default: 371 file_error(ms, 0, "invalid mode 0%o", sb->st_mode); 372 return -1; 373 /*NOTREACHED*/ 374 } 375 376 if (!mime && did) { 377 if (file_printf(ms, " ") == -1) 378 return -1; 379 } 380 return ret; 381 } 382